Keith Chen, an economist from Yale, makes a startling claim in an unpublished working paper: people’s fiscal responsibility and healthy lifestyle choices depend in part on the grammar of their language.

Here’s the idea: Languages differ in the devices they offer to speakers who want to talk about the future. For some, like Spanish and Greek, you have to tack on a verb ending that explicitly marks future time—so, in Spanish, you would say escribo for the present tense (I write or I’m writing) and escribiré for the future tense (I will write). But other languages like Mandarin don’t require their verbs to be escorted by grammatical markers that convey future time—time is usually obvious from something else in the context. In Mandarin, you would say the equivalent of I write tomorrow, using the same verb form for both present and future.

Chen’s finding is that if you divide up a large number of the world’s languages into those that require a grammatical marker for future time and those that don’t, you see an interesting correlation: speakers of languages that force grammatical marking of the future have amassed a smaller retirement nest egg, smoke more, exercise less, and are more likely to be obese. Why would this be? The claim is that a sharp grammatical division between the present and future encourages people to conceive of the future as somehow dramatically different from the present, making it easier to put off behaviors that benefit your future self rather than your present self.